SQL Query not using Composite Index

Hi,
Please look at the below query:
SELECT pde.participant_uid
,pde.award_code
,pde.award_type
,SUM(decode(pde.distribution_type
,'FORFEITURE'
,pde.forfeited_quantity *
pde.sold_price * cc.rate
,pde.distributed_quantity *
pde.sold_price * cc.rate)) AS gross_Amt_pref_Curr
FROM part_distribution_exec pde
,currency_conversion cc
,currency off_curr
WHERE pde.participant_uid = 4105
AND off_curr.currency_iso_code =
pde.offering_currency_iso_code
AND cc.from_currency_uid = off_curr.currency_uid
AND cc.to_currency_uid = 1
AND cc.latest_flag = 'Y'
GROUP BY pde.participant_uid
,pde.award_code
,pde.award_type
In oracle 9i, i"ve executed this above query, it takes 6 seconds and the cost is 616, this is due to non usage of the composite index, Currency_conversion_idx(From_currency_uid, To_currency_uid, Latest_flag). I wonder why this index is not used while executing the above query. So, I've dropped the index and recreated it. Now, the query is using this index. After inserting many rows or say in 1 days time, if the same query is executed, again the query is not using the index. So everyday, the index should be dropped and recreated.
I don't want this drop and recreation of index daily, I need a permanent solution for this.
Can anyone tell me, Why this index goes stale after a period of time???? Please take some time and Solve this issue.
-Sankar

Hi David,
This is Sankar here. Thankyou for your reply.
I've got the plan table output for this problematic query, please go thro' it and help me out why the index CURRENCY_CONVERSION_IDX is used now and why it's not using while executing the query after a day or inserting some records...
PLAN_TABLE_OUTPUT
| Id | Operation | Name | Rows | Bytes | Cost |
| 0 | SELECT STATEMENT | | 26 | 15678 | 147 |
| 1 | TABLE ACCESS BY INDEX ROWID | PART_AWARD_PAYOUT_SCHEDULE | 1 | 89 | 2 |
|* 2 | INDEX UNIQUE SCAN | PART_AWARD_PAYOUT_SCHEDULE_PK1 | 61097 | | 1 |
| 3 | SORT AGGREGATE | | 1 | 67 | |
|* 4 | FILTER | | | | |
|* 5 | INDEX RANGE SCAN | PART_AWARD_PAYOUT_SCHEDULE_PK1 | 1 | 67 | 2 |
| 6 | SORT AGGREGATE | | 1 | 94 | |
|* 7 | FILTER | | | | |
|* 8 | TABLE ACCESS BY INDEX ROWID | PART_AWARD_PAYOUT_SCHEDULE | 1 | 94 | 3 |
|* 9 | INDEX RANGE SCAN | PART_AWARD_PAYOUT_SCHEDULE_PK1 | 1 | | 2 |
|* 10 | FILTER | | | | |
|* 11 | HASH JOIN | | 26 | 15678 | 95 |
|* 12 | HASH JOIN OUTER | | 26 | 11596 | 91 |
|* 13 | HASH JOIN | | 26 | 10218 | 86 |
| 14 | VIEW | | 1 | 82 | 4 |
| 15 | SORT GROUP BY | | 1 | 116 | 4 |
|* 16 | TABLE ACCESS BY INDEX ROWID | PART_AWARD_LEDGER | 1 | 116 | 2 |
|* 17 | INDEX RANGE SCAN | PARTICIPANT_UID_IDX | 1 | | 1 |
|* 18 | HASH JOIN OUTER | | 26 | 8086 | 82 |
|* 19 | HASH JOIN | | 26 | 6006 | 71 |
| 20 | NESTED LOOPS | | 36 | 5904 | 66 |
| 21 | NESTED LOOPS | | 1 | 115 | 65 |
| 22 | TABLE ACCESS BY INDEX ROWID | CURRENCY_CONVERSION | 18 | 756 | 2 |
|* 23 | INDEX RANGE SCAN | KLS_IDX_CURRENCY_CONV | 3 | | 1 |
| 24 | VIEW | | 1 | 73 | 4 |
| 25 | SORT GROUP BY | | 1 | 71 | 4 |
| 26 | TABLE ACCESS BY INDEX ROWID| PART_AWARD_VALUE | 1 | 71 | 2 |
|* 27 | INDEX RANGE SCAN | PAV_PARTICIPANT_UID_IDX | 1 | | 1 |
| 28 | TABLE ACCESS BY INDEX ROWID | PARTICIPANT_AWARD | 199 | 9751 | 1 |
|* 29 | INDEX UNIQUE SCAN | PARTICIPANT_AWARD_PK1 | 100 | | |
|* 30 | INDEX FAST FULL SCAN | PARTICIPANT_AWARD_TYPE_PK1 | 147 | 9849 | 4 |
| 31 | VIEW | | 1 | 80 | 10 |
| 32 | SORT GROUP BY | | 1 | 198 | 10 |
|* 33 | TABLE ACCESS BY INDEX ROWID | CURRENCY_CONVERSION | 1 | 42 | 2 |
| 34 | NESTED LOOPS | | 1 | 198 | 8 |
| 35 | NESTED LOOPS | | 2 | 312 | 4 |
| 36 | TABLE ACCESS BY INDEX ROWID| PART_DISTRIBUTION_EXEC | 2 | 276 | 2 |
|* 37 | INDEX RANGE SCAN | IND_PARTICIPANT_UID | 1 | | 1 |
| 38 | TABLE ACCESS BY INDEX ROWID| CURRENCY | 1 | 18 | 1 |
|* 39 | INDEX UNIQUE SCAN | CURRENCY_AK | 1 | | |
|* 40 | INDEX RANGE SCAN | CURRENCY_CONVERSION_AK | 2 | | 1 |
| 41 | VIEW | | 1 | 53 | 4 |
| 42 | SORT GROUP BY | | 1 | 62 | 4 |
|* 43 | TABLE ACCESS BY INDEX ROWID | PART_AWARD_VESTING | 1 | 62 | 2 |
|* 44 | INDEX RANGE SCAN | PAVES_PARTICIPANT_UID_IDX | 1 | | 1 |
| 45 | TABLE ACCESS FULL | AWARD | 1062 | 162K| 3 |
| 46 | TABLE ACCESS BY INDEX ROWID | CURRENCY | 1 | 18 | 2 |
|* 47 | INDEX UNIQUE SCAN | CURRENCY_AK | 102 | | 1 |
Predicate Information (identified by operation id):
2 - access("PAPS"."AWARD_CODE"=:B1 AND "PAPS"."PARTICIPANT_UID"=4105 AND "PAPS"."AWARD_TYPE"=:B2
"PAPS"."INSTALLMENT_NUM"=1)
4 - filter(4105=:B1)
5 - access("PAPS"."AWARD_CODE"=:B1 AND "PAPS"."PARTICIPANT_UID"=4105 AND "PAPS"."AWARD_TYPE"=:B2)
7 - filter(4105=:B1)
8 - filter("PAPS"."STATUS"='OPEN')
9 - access("PAPS"."AWARD_CODE"=:B1 AND "PAPS"."PARTICIPANT_UID"=4105 AND "PAPS"."AWARD_TYPE"=:B2)
10 - filter("CC_A_P_CURR"."FROM_CURRENCY_UID"= (SELECT /*+ */ "CURRENCY"."CURRENCY_UID" FROM
"EWAPDBO"."CURRENCY" "CURRENCY" WHERE "CURRENCY"."CURRENCY_ISO_CODE"=:B1))
11 - access("SYS_ALIAS_7"."AWARD_CODE"="A"."AWARD_CODE")
12 - access("SYS_ALIAS_7"."AWARD_CODE"="PVS"."AWARD_CODE"(+))
13 - access("SYS_ALIAS_8"."AWARD_CODE"="PALS"."AWARD_CODE" AND
"SYS_ALIAS_8"."AWARD_TYPE"="PALS"."AWARD_TYPE")
16 - filter(TRUNC("PAL1"."LEDGER_ENTRY_DATE")<=TRUNC(SYSDATE@!) AND "PAL1"."ALLOC_TYPE"='IPU')
17 - access("PAL1"."PARTICIPANT_UID"=4105)
filter("PAL1"."PARTICIPANT_UID"=4105)
18 - access("SYS_ALIAS_8"."AWARD_CODE"="PDES"."AWARD_CODE"(+) AND
"SYS_ALIAS_8"."AWARD_TYPE"="PDES"."AWARD_TYPE"(+))
19 - access("SYS_ALIAS_7"."AWARD_CODE"="SYS_ALIAS_8"."AWARD_CODE")
23 - access("CC_A_P_CURR"."TO_CURRENCY_UID"=1 AND "CC_A_P_CURR"."LATEST_FLAG"='Y')
27 - access("PAV"."PARTICIPANT_UID"=4105)
filter("PAV"."PARTICIPANT_UID"=4105)
29 - access("SYS_ALIAS_7"."AWARD_CODE"="SYS_ALIAS_9"."AWARD_CODE" AND
"SYS_ALIAS_7"."PARTICIPANT_UID"=4105)
30 - filter("SYS_ALIAS_8"."PARTICIPANT_UID"=4105)
33 - filter("CC"."LATEST_FLAG"='Y')
37 - access("PDE"."PARTICIPANT_UID"=4105)
filter("PDE"."PARTICIPANT_UID"=4105)
39 - access("OFF_CURR"."CURRENCY_ISO_CODE"="PDE"."OFFERING_CURRENCY_ISO_CODE")
40 - access("CC"."FROM_CURRENCY_UID"="OFF_CURR"."CURRENCY_UID" AND "CC"."TO_CURRENCY_UID"=1)
43 - filter("PV"."VESTING_DATE"<=SYSDATE@!)
44 - access("PV"."PARTICIPANT_UID"=4105)
filter("PV"."PARTICIPANT_UID"=4105)
47 - access("CURRENCY"."CURRENCY_ISO_CODE"=:B1)
Note: cpu costing is off
93 rows selected.
Please help me out...
-Sankar

Similar Messages

Why is this query not using the index?

check out this query:-
SELECT CUST_PO_NUMBER, HEADER_ID, ORDER_TYPE, PO_DATE
FROM TABLE1
WHERE STATUS = 'N'
and here's the explain plan:-
1
2     -------------------------------------------------------------------------------------
3     | Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
4     -------------------------------------------------------------------------------------
5     | 0 | SELECT STATEMENT | | 2735K| 140M| 81036 (2)|
6     |* 1 | TABLE ACCESS FULL| TABLE1 | 2735K| 140M| 81036 (2)|
7     -------------------------------------------------------------------------------------
8
9     Predicate Information (identified by operation id):
10     ---------------------------------------------------
11
12     1 - filter("STATUS"='N')
There is already an index on this column, as is shown below:-
     INDEX_NAME INDEX_TYPE     UNIQUENESS     TABLE_NAME     COLUMN_NAME     COLUMN_POSITION
1     TABLE1_IDX2 NORMAL     NONUNIQUE     TABLE1      STATUS     1
2     TABLE1_IDX NORMAL     NONUNIQUE     TABLE1     HEADER_ID     1
So why is this query not using the index on the 'STATUS' Column?
I've already tried using optimizer hints and regathering the stats on the table, but the execution plan still remains the same, i.e. it still uses a FTS.
I have tried this command also:-
exec dbms_stats.gather_table_stats('GECS','GEPS_CS_SALES_ORDER_HEADER',method_opt=>'for all indexed columns size auto',cascade=>true,degree=>4);
inspite of this, the query is still using a full table scan.
The table has around 55 Lakh records, across 60 columns. And because of the FTS, the query is taking a long time to execute. How do i make it use the index?
Please help.
Edited by: user10047779 on Mar 16, 2010 6:55 AM

If the cardinality is really as skewed as that, you may want to look at putting a histogram on the column (sounds like it would be in order, and that you don't have one).
create table skewed_a_lot
as
   select
      case when mod(level, 1000) = 0 then 'N' else 'Y' end as Flag,
      level as col1
   from dual connect by level <= 1000000;
create index skewed_a_lot_i01 on skewed_a_lot (flag);
exec dbms_stats.gather_table_stats(user, 'SKEWED_A_LOT', cascade => true, method_opt => 'for all indexed columns size auto');Is an example.

Query not using the index

Query
SELECT case.case_objid FROM [email protected] case, table_x_cwp_tickect_details_vw t WHERE CASE.case_condition_cd IN ('OPEN', 'OPEN-DISPATCH', 'OPEN-REJECT', 'OPEN-RETURNED') AND case.case_type_cd in ('CUSTOMER FAULT', 'CHRONIC','SCHEDULED ACTIVITY','PROBLEM') AND ROWNUM <= 500 AND case.case_objid = t.ticket_objid AND ( ( case.account_id = '672286' ) ) ORDER BY case.case_id DESC
From PROD
Plan
SELECT STATEMENT HINT: FIRST_ROWS Cost: 2,629 Bytes: 221,500 Cardinality: 500
     37 SORT ORDER BY Cost: 2,629 Bytes: 221,500 Cardinality: 500
          36 COUNT STOPKEY
               35 NESTED LOOPS OUTER Cost: 2,628 Bytes: 279,533 Cardinality: 631
                    33 HASH JOIN OUTER Cost: 2,627 Bytes: 275,116 Cardinality: 631
                         31 NESTED LOOPS OUTER Cost: 2,249 Bytes: 266,282 Cardinality: 631
                              28 NESTED LOOPS Cost: 1,766 Bytes: 257,448 Cardinality: 631
                                   26 NESTED LOOPS Cost: 1,765 Bytes: 253,031 Cardinality: 631
                                        24 NESTED LOOPS Cost: 1,764 Bytes: 248,614 Cardinality: 631
                                             22 NESTED LOOPS Cost: 1,763 Bytes: 244,197 Cardinality: 631
                                                  19 NESTED LOOPS Cost: 1,258 Bytes: 235,363 Cardinality: 631
                                                       17 NESTED LOOPS Cost: 1,257 Bytes: 230,946 Cardinality: 631
                                                            14 NESTED LOOPS OUTER Cost: 752 Bytes: 217,695 Cardinality: 631
                                                                 12 HASH JOIN Cost: 751 Bytes: 213,278 Cardinality: 631
                                                                      1 INDEX FAST FULL SCAN INDEX (UNIQUE) SA.GBST_ELM_OBJINDEX Cost: 2 Bytes: 10,052 Cardinality: 1,436
                                                                      11 HASH JOIN Cost: 748 Bytes: 208,861 Cardinality: 631
                                                                           2 INDEX FAST FULL SCAN INDEX (UNIQUE) SA.GBST_ELM_OBJINDEX Cost: 2 Bytes: 10,052 Cardinality: 1,436
                                                                           10 HASH JOIN Cost: 746 Bytes: 204,444 Cardinality: 631
                                                                                3 INDEX FAST FULL SCAN INDEX (UNIQUE) SA.GBST_ELM_OBJINDEX Cost: 2 Bytes: 10,052 Cardinality: 1,436
                                                                                9 HASH JOIN Cost: 743 Bytes: 200,027 Cardinality: 631
                                                                                     4 INDEX FAST FULL SCAN INDEX (UNIQUE) SA.GBST_ELM_OBJINDEX Cost: 2 Bytes: 10,052 Cardinality: 1,436
                                                                                     8 NESTED LOOPS Cost: 741 Bytes: 195,610 Cardinality: 631
                                                                                          5 REMOTE REMOTE CASE Cost: 235 Bytes: 156,488 Cardinality: 631
                                                                                          7 TABLE ACCESS BY INDEX ROWID TABLE SA.TABLE_CASE Cost: 1 Bytes: 62 Cardinality: 1
                                                                                               6 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.TC_C_CASE_OBJINDEX Cost: 1 Cardinality: 1
                                                                 13 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.UN_PTT2CASE Cost: 1 Bytes: 7 Cardinality: 1
                                                            16 TABLE ACCESS BY INDEX ROWID TABLE SA.TABLE_SITE Cost: 1 Bytes: 21 Cardinality: 1
                                                                 15 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.SITE_OBJINDEX Cost: 1 Cardinality: 1
                                                       18 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.BUS_ORG_OBJINDEX Cost: 1 Bytes: 7 Cardinality: 1
                                                  21 TABLE ACCESS BY INDEX ROWID TABLE SA.TABLE_ADDRESS Cost: 1 Bytes: 14 Cardinality: 1
                                                       20 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.ADDRESS_OBJINDEX Cost: 1 Cardinality: 1
                                             23 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.COUNTRY_OBJINDEX Cost: 1 Bytes: 7 Cardinality: 1
                                        25 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.CONTACT_OBJINDEX Cost: 1 Bytes: 7 Cardinality: 1
                                   27 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.CONDITION_OBJINDEX Cost: 1 Bytes: 7 Cardinality: 1
                              30 TABLE ACCESS BY GLOBAL INDEX ROWID TABLE SA.TABLE_SITE_PART Cost: 1 Bytes: 14 Cardinality: 1 Partition #: 34
                                   29 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.SITE_PART_OBJINDEX Cost: 1 Cardinality: 1
                         bold 32 TABLE ACCESS FULL TABLE SA.TABLE_MOD_LEVEL Cost: 376 Bytes: 1,442,084 Cardinality: 103,006 bold
                    34 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.PART_NUM_OBJINDEX Cost: 1 Bytes: 7 Cardinality: 1
From DEV platform
Plan
SELECT STATEMENT HINT: FIRST_ROWS Cost: 591 Bytes: 61,134 Cardinality: 138
     37 SORT ORDER BY Cost: 591 Bytes: 61,134 Cardinality: 138
          36 COUNT STOPKEY
               35 HASH JOIN Cost: 590 Bytes: 61,134 Cardinality: 138
                    1 INDEX FAST FULL SCAN INDEX (UNIQUE) SA.GBST_ELM_OBJINDEX Cost: 2 Bytes: 10,045 Cardinality: 1,435
                    34 HASH JOIN Cost: 588 Bytes: 60,168 Cardinality: 138
                         2 INDEX FAST FULL SCAN INDEX (UNIQUE) SA.GBST_ELM_OBJINDEX Cost: 2 Bytes: 10,045 Cardinality: 1,435
                         33 HASH JOIN Cost: 585 Bytes: 59,202 Cardinality: 138
                              3 INDEX FAST FULL SCAN INDEX (UNIQUE) SA.GBST_ELM_OBJINDEX Cost: 2 Bytes: 10,045 Cardinality: 1,435
                              32 HASH JOIN Cost: 583 Bytes: 58,236 Cardinality: 138
                                   4 INDEX FAST FULL SCAN INDEX (UNIQUE) SA.GBST_ELM_OBJINDEX Cost: 2 Bytes: 10,045 Cardinality: 1,435
                                   31 NESTED LOOPS OUTER Cost: 580 Bytes: 57,270 Cardinality: 138
                                        29 NESTED LOOPS OUTER Cost: 579 Bytes: 56,304 Cardinality: 138
                                             27 NESTED LOOPS OUTER Cost: 469 Bytes: 54,372 Cardinality: 138
                                                  24 NESTED LOOPS Cost: 363 Bytes: 52,440 Cardinality: 138
                                                       22 NESTED LOOPS Cost: 362 Bytes: 51,474 Cardinality: 138
                                                            20 NESTED LOOPS Cost: 361 Bytes: 50,508 Cardinality: 138
                                                                 18 NESTED LOOPS Cost: 360 Bytes: 49,542 Cardinality: 138
                                                                      15 NESTED LOOPS Cost: 249 Bytes: 47,610 Cardinality: 138
                                                                           13 NESTED LOOPS Cost: 248 Bytes: 46,644 Cardinality: 138
                                                                                10 NESTED LOOPS OUTER Cost: 138 Bytes: 43,746 Cardinality: 138
                                                                                     8 NESTED LOOPS Cost: 137 Bytes: 42,780 Cardinality: 138
                                                                                          5 REMOTE REMOTE CASE Cost: 26 Bytes: 34,224 Cardinality: 138
                                                                                          7 TABLE ACCESS BY INDEX ROWID TABLE SA.TABLE_CASE Cost: 1 Bytes: 62 Cardinality: 1
                                                                                               6 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.TC_C_CASE_OBJINDEX Cost: 1 Cardinality: 1
                                                                                     9 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.UN_PTT2CASE Cost: 1 Bytes: 7 Cardinality: 1
                                                                                12 TABLE ACCESS BY INDEX ROWID TABLE SA.TABLE_SITE Cost: 1 Bytes: 21 Cardinality: 1
                                                                                     11 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.SITE_OBJINDEX Cost: 1 Cardinality: 1
                                                                           14 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.BUS_ORG_OBJINDEX Cost: 1 Bytes: 7 Cardinality: 1
                                                                      17 TABLE ACCESS BY INDEX ROWID TABLE SA.TABLE_ADDRESS Cost: 1 Bytes: 14 Cardinality: 1
                                                                           16 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.ADDRESS_OBJINDEX Cost: 1 Cardinality: 1
                                                                 19 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.COUNTRY_OBJINDEX Cost: 1 Bytes: 7 Cardinality: 1
                                                            21 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.CONTACT_OBJINDEX Cost: 1 Bytes: 7 Cardinality: 1
                                                       23 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.CONDITION_OBJINDEX Cost: 1 Bytes: 7 Cardinality: 1
                                                  26 TABLE ACCESS BY GLOBAL INDEX ROWID TABLE SA.TABLE_SITE_PART Cost: 1 Bytes: 14 Cardinality: 1 Partition #: 34
                                                       25 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.SITE_PART_OBJINDEX Cost: 1 Cardinality: 1
                                   bold           28 INDEX RANGE SCAN INDEX SA.IND_PART_INFO2PART_NUM Cost: 1 Bytes: 14 Cardinality: 1 bold
                                        30 INDEX UNIQUE SCAN INDEX (UNIQUE) SA.PART_NUM_OBJINDEX Cost: 1 Bytes: 7 Cardinality: 1
Conclusion:
IND_PART_INFO2PART_NUM is not in use in Production environment
PROD
1. SQL> select index_name,NUM_ROWS,CLUSTERING_FACTOR from dba_indexes where index_name='IND_PART_INFO2PART_NUM';
INDEX_NAME NUM_ROWS CLUSTERING_FACTOR
IND_PART_INFO2PART_NUM 103023 46488
DEV environment
SQL> select index_name,NUM_ROWS,CLUSTERING_FACTOR,table_name from dba_indexes where index_name='IND_PART_INFO2PART_NUM';
INDEX_NAME NUM_ROWS CLUSTERING_FACTOR TABLE_NAME
IND_PART_INFO2PART_NUM 101982 45722 TABLE_MOD_LEVEL
1. Index is rebuild
2. stats are up to date
3. Redef on table is done.
Still no change in the plan .

Osama-mustafa wrote:
Aman.... wrote:
Osama-mustafa wrote:
alter index <index-name> rebuild ;Why?
Aman....I faced this issue with query and indexes was need rebuildWhat issue Osama-that query wasn't using index and after rebuild it did start using it? Not just that this reply is wrong , this is OP has mentioned that he has done already. Please note that index rebuild is not the answer when the query is not using the index. There can be many reasons behind it. Have a look at Richard Foote's blog where he explains all of this in a very detailed way and in many posts.
Aman....

Why my query not using any index but doing a FULL TABLE SCAN

Hi,
My EXPLAIN PLAN output is
Plan hash value: 1163866984
| Id | Operation               | Name              | Rows | Bytes |TempSpc| Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT        |                   |   774 |   159K|       | 40847   (2)| 00:08:11 |
|* 1 | FILTER                 |                   |       |       |       |            |          |
|   2 |   SORT GROUP BY         |                   |   774 |   159K|       | 40847   (2)| 00:08:11 |
|* 3 |    HASH JOIN            |                   | 77337 |    15M| 9744K| 40843   (2)| 00:08:11 |
|* 4 |     HASH JOIN           |                   | 77337 | 8836K| 5896K| 20987   (2)| 00:04:12 |
|* 5 |      HASH JOIN          |                   | 77337 | 4984K|       | 9292   (3)| 00:01:52 |
|* 6 |       HASH JOIN         |                   | 24991 |   951K|       | 3349   (3)| 00:00:41 |
|* 7 |        TABLE ACCESS FULL| IDS_TXNIDNUMBERS | 24991 |   683K|       | 2328   (3)| 00:00:28 |
|   8 |        TABLE ACCESS FULL| IDS_TXNDEMDATAMAP | 2419K|    25M|       | 1006   (3)| 00:00:13 |
|   9 |       TABLE ACCESS FULL | IDS_IDNUMBERS     | 7435K|   191M|       | 5903   (2)| 00:01:11 |
| 10 |      TABLE ACCESS FULL | IDS_DEMDATA       | 2583K|   125M|       | 3683   (5)| 00:00:45 |
| 11 |     TABLE ACCESS FULL   | IDS_TXN           | 2583K|   231M|       | 6403   (1)| 00:01:17 |
----------------------------------------------------------------------------------------------------- All my 5 tables IDS_TXNIDNUMBERS, IDS_TXNDEMDATAMAP, IDS_IDNUMBERS,IDS_DEMDATA, IDS_TXN has indexes in relevant columns. Is it cause less time so CBO is not using the indexes.
Thanks
Amitava.

amitavachatterjee1975 wrote:
Please be polite when responding to my queries. If you find these questions not to your standard, stay away from them. This is an open forum and I have got my full rights to ask questions.Unsure, what wrong did you find in SB's reply. I find those links perfectly knowledgeable. The question of having so many unanswered questions probably pricked you a little too much. But that, IMO, is a legitimate question, to be asked to a User who even after being associated with OTN for over an year has 100% record of not getting an answer.
For your original question, you will have to provide more details to allow people to answer you.
You must read {message:id=3292438} and post the mentioned details. People do not carry a Crystal Ball to identify the problem merely by reading few lines of Problem description and Explain plans. Do not make people guess, provide appropriate details, to help them Help "You".

Why is this query not using my index ?

hey
i have the following situation
(i'm sorry but i can't add the acctual script or output)
create table x as
select      level high_card ,
     mod(level,1000) medium_card ,
     mod(level,10) low_card ,
     '***' padding
from     dual
connect by level < 100001;
create index x_med_low_ix on x(low_card,medium_card);
create index x_high_ix on x(high_card);
exec dbms_stats.gather_table_stats(user,'x',cascade=>true,method_opt=>'for all indexed columns size auto');
i'm running the following query
select      *
from      x
where      low_card = 70
and     medium_card = 70
and     high_card = 70;
i'm expecting a range scan on the x_high_ix index. the optimizer expects only one row. the stats on the high_card columns shows that (num_rows * density = 1).
when i run the query the optimizer uses the x_med_low_ix and does 14 cr.
when i force the use of x_high_ix the cr goes down to 4.
i don't want to declare x_high_ix as unique.
so, why isn't he using my index ?

It's using that index for me:
SQL> create table x as
2 select level high_card ,
3 mod(level,1000) medium_card ,
4 mod(level,10) low_card ,
5 '***' padding
6 from dual
7 connect by level < 100001;
Table created.
SQL>
SQL> create index x_med_low_ix on x(low_card,medium_card);
Index created.
SQL>
SQL> create index x_high_ix on x(high_card);
Index created.
SQL>
SQL> exec dbms_stats.gather_table_stats(user,'x',cascade=>true,method_opt=>'for all indexed columns
size auto');
PL/SQL procedure successfully completed.
SQL> ed
Wrote file afiedt.buf
1   select *
2   from x
3   where low_card = 70
4   and medium_card = 70
5* and high_card = 70
SQL>
SQL> /
no rows selected
Execution Plan
Plan hash value: 775193209
| Id | Operation                   | Name      | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT            |           |     1 |    15 |     2   (0)| 00:00:01 |
|* 1 | TABLE ACCESS BY INDEX ROWID| X         |     1 |    15 |     2   (0)| 00:00:01 |
|* 2 |   INDEX RANGE SCAN          | X_HIGH_IX |     1 |       |     1   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   1 - filter("LOW_CARD"=70 AND "MEDIUM_CARD"=70)
   2 - access("HIGH_CARD"=70)
Statistics
          0 recursive calls
          0 db block gets
          3 consistent gets
          0 physical reads
          0 redo size
        454 bytes sent via SQL*Net to client
        370 bytes received via SQL*Net from client
          1 SQL*Net roundtrips to/from client
          0 sorts (memory)
          0 sorts (disk)
          0 rows processed
SQL> set autot off
SQL> select * from v$version;
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
PL/SQL Release 10.2.0.1.0 - Production
CORE    10.2.0.1.0      Production
TNS for 32-bit Windows: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Productionwhat is your version?
By the way, when i force optimizer to use index X_MED_LOW_IX, it does 2 CR for me.

Spatial Query not using Spatial Index

Hi All,
I have a query which uses the SDO_WITHIN_DISTANCE operator, but is taking far too long to complete.
SELECT
               RT.*,RD.RPD_NODE_ID, RD.RPD_XCOORD,RD.RPD_YCOORD
          FROM
               railplan_data RD
               LEFT JOIN Walk_data_sets WDS ON RD.RPD_RPS_ID = WDS.WDS_RPS_ID
               LEFT JOIN RWNet_Temp RT ON WDS.WDS_ID = RT.RW_WDS_ID
          WHERE
               WDS.wds_id = 441
          AND
               MDSYS.SDO_WITHIN_DISTANCE(RT.RW_GEOM,RD.RPD_GEOLOC,'DISTANCE=' || TO_CHAR(RT.RW_BUFFER) || ' UNIT=METER') = 'TRUE';
Upon generation of the explain plan I have realised that the spatial index is not being used in the query, but I can't for the life of me get the thing working
3     | Id | Operation | Name | Rows | Bytes |TempSpc| Cost |
4     ------------------------------------------------------------------------------------------
5     | 0 | SELECT STATEMENT | | 25841 | 99M| | 201 |
6     |* 1 | FILTER | | | | | |
7     | 2 | MERGE JOIN OUTER | | | | | |
8     |* 3 | HASH JOIN | | 12652 | 420K| 2968K| 185 |
9     | 4 | TABLE ACCESS FULL | RAILPLAN_DATA | 75910 | 2075K| | 60 |
10     | 5 | TABLE ACCESS BY INDEX ROWID| WALK_DATA_SETS | 1 | 6 | | 1 |
11     |* 6 | INDEX UNIQUE SCAN | WDS_PK | 1 | | | |
12     |* 7 | SORT JOIN | | 16 | 63760 | | 16 |
13     |* 8 | TABLE ACCESS FULL | RWNET_TEMP | 16 | 63760 | | 4 |
If anyone could help me out in figuring out why the spatial index is not being used, I would be most appreciative.
TIA
Dan

Hi all again,
Well I finally got an upgrade to Oracle 10 (yay!), so I am now trying to implement the SDO_JOIN method as per my earlier posts. In fact it is actually working, but I have a question. When I run an explain plan it does not show the use of any domain indexes which I would expect to see, but performs fine (1.07s) with just a few records (10 in 1 table, 15000 in the other), please see code and explain plan below:
SELECT
Distinct
    RT.RW_ID, RD.RPD_NODE_ID,
    RD.RPD_XCOORD,RD.RPD_YCOORD
FROM
    RPD_TEMP_762 RD,
    WALK_DATA_SETS WDS,
    RWNET_TEMP RT,
    TABLE
    (SDO_JOIN
        ( 'RWNET_TEMP',
            'RW_GEOM',
            'RPD_TEMP_762',
            'RPD_GEOLOC',
            'distance= ' || TO_CHAR(RT.RW_BUFFER) || ' unit=meter')) SPATIAL_JOIN_RESULT
WHERE WDS.WDS_ID = RT.RW_WDS_ID
AND WDS.WDS_ID = 762
AND SPATIAL_JOIN_RESULT.ROWID1 = RT.ROWID
AND SPATIAL_JOIN_RESULT.ROWID2 = RD.ROWID
PLAN_TABLE_OUTPUT
| Id | Operation                            | Name         | Rows | Bytes | Cost (%CPU)|
|   0 | SELECT STATEMENT                     |              |    74 | 5994 | 21753   (1)|
|   1 | SORT UNIQUE                         |              |    74 | 5994 | 21691   (1)|
|* 2 |   HASH JOIN                          |              | 1046K|    80M| 1859   (1)|
|   3 |    NESTED LOOPS                      |              | 6076 |   213K| 1824   (1)|
|   4 |     NESTED LOOPS                     |              |    74 | 2516 |   194   (1)|
|* 5 |      INDEX UNIQUE SCAN               | WDS_PK       |     1 |     4 |     0   (0)|
|* 6 |      TABLE ACCESS FULL               | RWNET_TEMP   |    74 | 2220 |   194   (1)|
|* 7 |     COLLECTION ITERATOR PICKLER FETCH| SDO_JOIN     |       |       |            |
|   8 |    TABLE ACCESS FULL                 | RPD_TEMP_762 | 17221 |   756K|    28   (0)|
------------------------------------------------------------------------------------------ When i try to add hints to force the use of spatial indexes the performance of this query drops through the floor (it takes minutes / hours), index hint shown below:
/*+ ORDERED INDEX(RW rw_geom) INDEX(RD rpd_geoloc) */My question is is the first query using domain indexes, and if not, how do I get it to?
TIA
Dan

Sql query not using parallel option

I am working in oracle 11.2.0.2.0 .
I am trying to execute one query using parallel options but in explain plan it is not using that PX option ...
UPDATE /*+PARALLEL (emp,4) */
cust_sku_allocation_data emp
set emp.mean=
(select sum(dep.stock_to_sales)/count(distinct dep.destination_facility)
FROM cust_sku_allocation dep
WHERE dep.stock_to_sales_ratio NOT IN (0,9999)
AND dep.sku_id = emp.sku_id);
Any idea where to check..

Sorry I meant:
You cannot parallelize UPDATE or DELETE operations on a nonpartitioned table, or when the update only affects 1 partition in a partitioned one.

"Improving SQL query performance using secondary indexes"

I have a very old copy of this document from 1997. I'm hoping to find newer version, if one exists, but the search facility on SDN is not working at the moment. Does anyone have a more up to date copy or link they can point me to ?
thanks,
Malcolm.

HI,
check it out , may be it will help you
[http://www.stanford.edu/dept/itss/docs/oracle/10g/server.101/b10743/schema.htm]
[http://teradata.uark.edu/research/wang/indexes.html]
[http://www.geekinterview.com/question_details/33720]

Why does it not use the index?

L.S.,
We are using a table called IT_RFC_REGISTRATION. It is a relatively big table for our application.
Its primary key is RFCNR, each new RFCNR getting the next value.
Now for my intranet report I am interested in the last 40 records. But when I execute:
SELECT *
FROM IT_RFC_REGISTRATION
ORDER BY RFCNR DESC
the query takes ages to execute.
When I do this:
SELECT RFCNR
FROM IT_RFC_REGISTRATION
ORDER BY RFCNR DESC
the result comes instantaneous because this query uses the index on RFCNR.
Why does the former query not use the index to execute? It should be much faster to fetch ROWIDs from the index end to start and use those to get the records, than to load all the records and then sort them.
Is there a trick with which I can use a join of the latter query and the former query to speed up the result?
Greetings,
Philbert de Zwart,
Utrecht, The Netherlands.

The difference you see in query run time is based on the amount data being sorted, then returned. In the first query, a full table scan is faster since if the index was used, Oracle would have to do a lookup in the index, get the rowid's and go look up the data in the table (TWO disk i/o's). It's faster to just scan the entire table.
Indexes will generally not be used unless you have a where clause. If you only need a few fields from the table, you could include them all in an index. For instance, if you only need RFCNR & DESC create a concatenated index on those two columns and then only a scan of the index is required (very fast).

Query not using indexes

select *
          from hrm_career x
          WHERE x.begin_date = ( SELECT MAX(begin_date)
                         FROM hrm_career y
                         WHERE y.employee_id = x.employee_id AND
                              begin_date <= SYSDATE AND
                              primary_job = 'Y') AND
               x.primary_job = 'Y'
I have the above query which is not using the index created on the BEGIN_DT column
I tried to force using still not using
but when i apply a value say
select *
          from hrm_career x
          WHERE x.begin_date ='10-20-2007'
It is using index and resulting in very fast response
Can some throw some ideas on it...
Where should i look into here ..

SQL> set autotrace traceonly
SQL> select *
2 from hrm_career x
3 WHERE x.begin_date = ( SELECT MAX(begin_date)
4 FROM hrm_career y
5 WHERE y.employee_id = x.employee_id AND
6 begin_date <= SYSDATE AND
7 primary_job = 'Y') AND
8 x.primary_job = 'Y';
13454 rows selected.
Execution Plan
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=1417 Card=152 Bytes=
35568)
1 0 FILTER
2 1 SORT (GROUP BY) (Cost=1417 Card=152 Bytes=35568)
3 2 HASH JOIN (Cost=254 Card=47127 Bytes=11027718)
4 3 INDEX (FAST FULL SCAN) OF 'HRM_CAREER_PK' (UNIQUE) (
Cost=12 Card=25026 Bytes=500520)
5 3 TABLE ACCESS (FULL) OF 'HRM_CAREER' (Cost=81 Card=25
335 Bytes=5421690)
Statistics
3671 recursive calls
9 db block gets
1758 consistent gets
2130 physical reads
0 redo size
2217762 bytes sent via SQL*Net to client
10359 bytes received via SQL*Net from client
898 SQL*Net roundtrips to/from client
128 sorts (memory)
1 sorts (disk)
13454 rows processed
TKPROF
TKPROF: Release 9.2.0.6.0 - Production on Wed Dec 12 18:40:56 2007
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Trace file: qnhg_ora_500.trc
Sort options: default
count = number of times OCI procedure was executed
cpu = cpu time in seconds executing
elapsed = elapsed time in seconds executing
disk = number of physical reads of buffers from disk
query = number of buffers gotten for consistent read
current = number of buffers gotten in current mode (usually for update)
rows = number of rows processed by the fetch or execute call
ALTER SESSION SET EVENTS '10046 trace name context forever, level 8'
call count cpu elapsed disk query current rows
Parse 0 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
total 1 0.00 0.00 0 0 0 0
Misses in library cache during parse: 0
Misses in library cache during execute: 1
Optimizer goal: CHOOSE
Parsing user id: 30 (ADMIN)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 1 0.00 0.00
SQL*Net message from client 1 34.45 34.45
select condition
from
cdef$ where rowid=:1
call count cpu elapsed disk query current rows
Parse 4 0.00 0.00 0 0 0 0
Execute 4 0.00 0.00 0 0 0 0
Fetch 4 0.00 0.00 0 8 0 4
total 12 0.00 0.00 0 8 0 4
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: SYS (recursive depth: 1)
Rows Row Source Operation
1 TABLE ACCESS BY USER ROWID CDEF$
select *
from hrm_career x
WHERE x.begin_date = ( SELECT MAX(begin_date)
FROM hrm_career y
WHERE y.employee_id = x.employee_id AND
begin_date <= SYSDATE AND
primary_job = 'Y') AND
x.primary_job = 'Y'
call count cpu elapsed disk query current rows
Parse 1 0.00 0.07 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 898 0.00 2.39 2038 946 9 13454
total 900 0.00 2.46 2038 946 9 13454
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: 30 (ADMIN)
Rows Row Source Operation
13454 FILTER
25335 SORT GROUP BY
67496 HASH JOIN
25333 INDEX FAST FULL SCAN HRM_CAREER_PK (object id 25292)
25336 TABLE ACCESS FULL HRM_CAREER
Rows Execution Plan
0 SELECT STATEMENT GOAL: CHOOSE
13454 FILTER
25335 SORT (GROUP BY)
67496 HASH JOIN
25333 INDEX GOAL: ANALYZED (FAST FULL SCAN) OF 'HRM_CAREER_PK'
(UNIQUE)
25336 TABLE ACCESS GOAL: ANALYZED (FULL) OF 'HRM_CAREER'
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 898 0.00 0.00
SQL*Net more data to client 877 0.00 0.05
db file sequential read 1 0.01 0.01
db file scattered read 60 0.00 0.14
direct path write 9 0.00 0.00
direct path read 125 0.05 0.13
SQL*Net message from client 898 0.02 1.47
DELETE FROM PLAN_TABLE
WHERE
STATEMENT_ID=:1
call count cpu elapsed disk query current rows
Parse 2 0.00 0.00 0 0 0 0
Execute 2 0.00 0.00 0 6 6 6
Fetch 0 0.00 0.00 0 0 0 0
total 4 0.00 0.00 0 6 6 6
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: 30 (ADMIN)
Rows Row Source Operation
0 DELETE
0 TABLE ACCESS FULL PLAN_TABLE
Rows Execution Plan
0 DELETE STATEMENT GOAL: CHOOSE
0 DELETE OF 'PLAN_TABLE'
0 TABLE ACCESS (FULL) OF 'PLAN_TABLE'
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 2 0.00 0.00
SQL*Net message from client 2 14.77 14.79
select o.owner#,o.name,o.namespace,o.remoteowner,o.linkname,o.subname,
o.dataobj#,o.flags
from
obj$ o where o.obj#=:1
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 1 0.00 0.00 0 3 0 1
total 3 0.00 0.00 0 3 0 1
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: SYS (recursive depth: 1)
EXPLAIN PLAN SET STATEMENT_ID='PLUS74964' FOR select *
from hrm_career x
WHERE x.begin_date = ( SELECT MAX(begin_date)
FROM hrm_career y
WHERE y.employee_id = x.employee_id AND
begin_date <= SYSDATE AND
primary_job = 'Y') AND
x.primary_job = 'Y'
call count cpu elapsed disk query current rows
Parse 1 0.00 0.01 0 4 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
total 2 0.00 0.01 0 4 0 0
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: 30 (ADMIN)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 1 0.00 0.00
SQL*Net message from client 1 0.00 0.00
insert into plan_table (statement_id, timestamp, operation, options,
object_node, object_owner, object_name, object_instance, object_type,
search_columns, id, parent_id, position, other,optimizer, cost, cardinality,
bytes, other_tag, partition_start, partition_stop, partition_id,
distribution, cpu_cost, io_cost, temp_space, access_predicates,
filter_predicates )
values
(:1,SYSDATE,:2,:3,:4,:5,:6,:7,:8,:9,:10,:11,:12,:13,:14,:15,:16,:17,:18,:19,
:20,:21,:22,:23,:24,:25,:26,:27)
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 6 0.00 0.00 0 3 6 6
Fetch 0 0.00 0.00 0 0 0 0
total 7 0.00 0.00 0 3 6 6
Misses in library cache during parse: 1
Misses in library cache during execute: 2
Optimizer goal: CHOOSE
Parsing user id: 30 (ADMIN) (recursive depth: 1)
Rows Execution Plan
0 INSERT STATEMENT GOAL: CHOOSE
select o.name, u.name
from
sys.obj$ o, sys.user$ u where obj# = :1 and owner# = user#
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 0 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
total 1 0.00 0.00 0 0 0 0
Misses in library cache during parse: 1
Parsing user id: SYS (recursive depth: 1)
SELECT ID ID_PLUS_EXP,PARENT_ID PARENT_ID_PLUS_EXP,LPAD(' ',2*(LEVEL-1))
||OPERATION||DECODE(OTHER_TAG,NULL,'','*')||DECODE(OPTIONS,NULL,'','
('||OPTIONS||')')||DECODE(OBJECT_NAME,NULL,'',' OF '''||OBJECT_NAME||'''')
||DECODE(OBJECT_TYPE,NULL,'',' ('||OBJECT_TYPE||')')||DECODE(ID,0,
DECODE(OPTIMIZER,NULL,'',' Optimizer='||OPTIMIZER))||DECODE(COST,NULL,'','
(Cost='||COST||DECODE(CARDINALITY,NULL,'',' Card='||CARDINALITY)
||DECODE(BYTES,NULL,'',' Bytes='||BYTES)||')') PLAN_PLUS_EXP,OBJECT_NODE
OBJECT_NODE_PLUS_EXP
FROM
PLAN_TABLE START WITH ID=0 AND STATEMENT_ID=:1 CONNECT BY PRIOR ID=PARENT_ID
AND STATEMENT_ID=:1 ORDER BY ID,POSITION
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 2 0.00 0.00 0 22 0 6
total 4 0.00 0.00 0 22 0 6
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: 30 (ADMIN)
Rows Row Source Operation
6 SORT ORDER BY
6 CONNECT BY WITH FILTERING
1 NESTED LOOPS
1 TABLE ACCESS FULL PLAN_TABLE
1 TABLE ACCESS BY USER ROWID PLAN_TABLE
5 NESTED LOOPS
6 BUFFER SORT
6 CONNECT BY PUMP
5 TABLE ACCESS FULL PLAN_TABLE
Rows Execution Plan
0 SELECT STATEMENT GOAL: CHOOSE
6 SORT (ORDER BY)
6 CONNECT BY (WITH FILTERING)
1 NESTED LOOPS
1 TABLE ACCESS (FULL) OF 'PLAN_TABLE'
1 TABLE ACCESS (BY USER ROWID) OF 'PLAN_TABLE'
5 NESTED LOOPS
6 BUFFER (SORT)
6 CONNECT BY PUMP
5 TABLE ACCESS (FULL) OF 'PLAN_TABLE'
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 2 0.00 0.00
SQL*Net message from client 2 0.09 0.09
SELECT ID ID_PLUS_EXP,OTHER_TAG OTHER_TAG_PLUS_EXP,OTHER OTHER_PLUS_EXP
FROM
PLAN_TABLE WHERE STATEMENT_ID=:1 AND OTHER_TAG IS NOT NULL ORDER BY ID
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 1 0.00 0.00 0 3 0 0
total 3 0.00 0.00 0 3 0 0
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: 30 (ADMIN)
Rows Row Source Operation
0 SORT ORDER BY
0 TABLE ACCESS FULL PLAN_TABLE
Rows Execution Plan
0 SELECT STATEMENT GOAL: CHOOSE
0 SORT (ORDER BY)
0 TABLE ACCESS (FULL) OF 'PLAN_TABLE'
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 2 0.00 0.00
SQL*Net message from client 2 0.00 0.00
ALTER SESSION SET EVENTS '10046 trace name context off'
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
total 2 0.00 0.00 0 0 0 0
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: 30 (ADMIN)
OVERALL TOTALS FOR ALL NON-RECURSIVE STATEMENTS
call count cpu elapsed disk query current rows
Parse 7 0.00 0.09 0 4 0 0
Execute 8 0.00 0.00 0 6 6 6
Fetch 901 0.00 2.39 2038 971 9 13460
total 916 0.00 2.49 2038 981 15 13466
Misses in library cache during parse: 6
Misses in library cache during execute: 1
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 906 0.00 0.00
SQL*Net message from client 906 34.45 50.82
SQL*Net more data to client 877 0.00 0.05
db file sequential read 1 0.01 0.01
db file scattered read 60 0.00 0.14
direct path write 9 0.00 0.00
direct path read 125 0.05 0.13
OVERALL TOTALS FOR ALL RECURSIVE STATEMENTS
call count cpu elapsed disk query current rows
Parse 7 0.00 0.00 0 0 0 0
Execute 11 0.00 0.00 0 3 6 6
Fetch 5 0.00 0.00 0 11 0 5
total 23 0.00 0.00 0 14 6 11
Misses in library cache during parse: 4
Misses in library cache during execute: 2
9 user SQL statements in session.
6 internal SQL statements in session.
15 SQL statements in session.
5 statements EXPLAINed in this session.
Trace file: qnhg_ora_500.trc
Trace file compatibility: 9.02.00
Sort options: default
3 sessions in tracefile.
12 user SQL statements in trace file.
8 internal SQL statements in trace file.
15 SQL statements in trace file.
11 unique SQL statements in trace file.
5 SQL statements EXPLAINed using schema:
ADMIN.prof$plan_table
Default table was used.
Table was created.
Table was dropped.
3945 lines in trace file.
Message was edited by:
Maran Viswarayar

Why is my SQL not using an index?

I have a small SQL query (10g) where I join to basic table together on a customer_id column.
select *
from customer c
inner join work_item sp1 ON sp1.customer_id = c.customer_id
and I am using TOAD, which tells me (in the Explain Plan area), that I'm doing a "TABLE ACCESS FULL" scan on the customer table.
But when I look at the details of BOTH tables, I can clearly see that they both have an index on the customer field, and they are both the same data types...
The interesting thing, is that if I change the query to only select data from the work_item table,
select sp1.*
from customer c
inner join work_item sp1 ON sp1.customer_id = c.customer_id
I can see that the indexes are being used...
Why is this? I must be able to select certain columns from the customer table, but why would it not use an index when I do?
Thanks!

If I understand correctly, below is a simple test case.
I created a small table and indexed "object_id" column.
When I issue "Select * from t" optimizer goes with FULL TABLE SCAN, whereas wehn "select OBJECT_ID from t" is issued, optimizer chooses to read from the index instead of accessing the table. This is because FAST FULL SCAN is far cheaper than a FTS in this case.
SQL> create table t as select object_id, object_name from all_objects;
Table created.
SQL> exec dbms_stats.gather_table_stats(user, 't');
PL/SQL procedure successfully completed.
SQL> create index t_idx1 on t(object_id);
Index created.
SQL> set autotrace traceonly exp
SQL> select * from t;
Execution Plan
Plan hash value: 1601196873
| Id | Operation         | Name | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT |      | 37932 | 1074K|    55   (2)| 00:00:01 |
| 1 | TABLE ACCESS FULL| T | 37932 | 1074K| 55 (2)| 00:00:01 |
SQL> select object_id from t;
Execution Plan
Plan hash value: 3958994525
| Id | Operation            | Name   | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT     |        | 37932 |   185K|    25   (0)| 00:00:01 |
| 1 | INDEX FAST FULL SCAN| T_IDX1 | 37932 | 185K| 25 (0)| 00:00:01 |
SQL>

Sql query not executed using recordset

Hi All,
I am trying to first format and then execute SQL query statement using recordset object with DI API. the issue is with vb.net's string formatting. I want to use 'USE [DB_Name]' statement in SQL and then 'Alter Procedure ..' statement. as this has to be the first statement in sql , I am using 'GO' in between and seperating each sentence with following syntax.
Dim AltProc as string
AltProc = " USE [DB_name]" & Environment.NewLine
AltProc = AltProc & " GO " & Environment.NewLine
AltProc = AltProc & " ALTER proc [proc_name] " & Environment.NewLine
'---------------------and so on
Orec.DoQuery(AltProc)
this formatting does not recognize new line and gives 'incorrect syntax near 'Go'' error. strange thing is, if I take this query in SQL, it runs perfectly and I can see it getting formatted with each new line created. I tried even VbcrLf but it didnt work.
any one has any idea?
thanks in advance,
Binita

HI Binita
The reason:
GO is the "command" delimiter of MS Query Editor.
It is not working with RecordSet Object.
In MS SQL 2008 version you can define the schema before the procedure name but in SQL server 2000/2005 it is not possible.
IN SQL 2008 use the Fully Qualified name instead of GO:
Dim AltProc as string
AltProc = " ALTER proc [DB_name].[dbo].[proc_name] " + vbcrlf
'---------------------and so on
Orec.DoQuery(AltProc)
it is not working on MS SQL 2008 i have tried.
'CREATE/ALTER PROCEDURE' does not allow specifying the database name as a prefix to the object name.'
Regards,
J.
Edited by: Janos Nagy on Jun 22, 2009 2:55 PM

How can i know if my query is using the index ?

Hello...
How can i know if my query is using the index of the table or not?
im using set autotrace on...but is there another way to do it?
thanks!
Alessandro Falanque.

Hi,
You can use Explain Plan for checking that your query is using proper index or not. First you need to check that Plan_table is installed in your database or not. If it is not there THEN THE SCRIPT WILL BE LIKE THIS:
CREATE TABLE PLAN_TABLE (
STATEMENT_ID VARCHAR2 (30),
TIMESTAMP DATE,
REMARKS VARCHAR2 (80),
OPERATION VARCHAR2 (30),
OPTIONS VARCHAR2 (30),
OBJECT_NODE VARCHAR2 (128),
OBJECT_OWNER VARCHAR2 (30),
OBJECT_NAME VARCHAR2 (30),
OBJECT_INSTANCE NUMBER,
OBJECT_TYPE VARCHAR2 (30),
OPTIMIZER VARCHAR2 (255),
SEARCH_COLUMNS NUMBER,
ID NUMBER,
PARENT_ID NUMBER,
POSITION NUMBER,
COST NUMBER,
CARDINALITY NUMBER,
BYTES NUMBER,
OTHER_TAG VARCHAR2 (255),
PARTITION_START VARCHAR2 (255),
PARTITION_STOP VARCHAR2 (255),
PARTITION_ID NUMBER,
OTHER LONG,
DISTRIBUTION VARCHAR2 (30))
TABLESPACE SYSTEM NOLOGGING
PCTFREE 10
PCTUSED 40
INITRANS 1
MAXTRANS 255
STORAGE (
INITIAL 10240
NEXT 10240
PCTINCREASE 50
MINEXTENTS 1
MAXEXTENTS 121
FREELISTS 1 FREELIST GROUPS 1 )
NOCACHE;
After that write the following command in the SQL prompt.
Explain plan for (Select statement);
Select level, SubStr( lpad(' ',2*(Level-1)) || operation || ' ' ||
object_name || ' ' || options || ' ' ||
decode(id, null , ' ', decode(position, null,' ', 'Cost = ' || position) ),1,100)
|| ' ' || nvl(other_tag, ' ') Operation
from PLAN_TABLE
start with id = 0
connect by
prior id = parent_id;
This will show how the query is getting executed . What are all the indexes it is using etc.
Cheers.
Samujjwal Basu

Can I refactor this query to use an index more efficiently?

I have a members table with fields such as id, last name, first name, address, join date, etc.
I have a unique index defined on (last_name, join_date, id).
This query will use the index for a range scan, no sort required since the index will be in order for that range ('Smith'):
SELECT members.*
        FROM members
        WHERE last_name = 'Smith'
        ORDER BY joindate, idIs there any way I can get something like the following to use the index (with no sort) as well:
SELECT members.*
        FROM members
        WHERE last_name like 'S%'
        ORDER BY joindate, idI understand the difficulty is probably; even if it does a range scan on every last name 'S%' (assuming it can?), they're not necessarily in order. Case in point:
Last_Name: JoinDate:
Smith          2/5/2010
Smuckers     1/10/2010An index range scan of 'S%' would return them in the above order, which is not ordered by joindate.
So is there any way I can refactor this (query or index) such that the index can be range scanned (using LIKE 'x%') and return rows in the correct order without performing a sort? Or is that simply not possible?

xaeryan wrote:
I have a members table with fields such as id, last name, first name, address, join date, etc.
I have a unique index defined on (last_name, join_date, id).
This query will use the index for a range scan, no sort required since the index will be in order for that range ('Smith'):
SELECT members.*
FROM members
WHERE last_name = 'Smith'
ORDER BY joindate, idIs there any way I can get something like the following to use the index (with no sort) as well:
SELECT members.*
FROM members
WHERE last_name like 'S%'
ORDER BY joindate, idI understand the difficulty is probably; even if it does a range scan on every last name 'S%' (assuming it can?), they're not necessarily in order. Case in point:
Last_Name: JoinDate:
Smith          2/5/2010
Smuckers     1/10/2010An index range scan of 'S%' would return them in the above order, which is not ordered by joindate.
So is there any way I can refactor this (query or index) such that the index can be range scanned (using LIKE 'x%') and return rows in the correct order without performing a sort? Or is that simply not possible?Come on. Index column order does matter. "LIKE 'x%'" actually is full table scan. The db engine accesses contiguous index entries and then uses the ROWID values in the index to retrieve the table rows.

Why is Oracle not using the index??

Hi,
I have a table called 'arc_errors' which has an index on 'member_number' as follows:- Create/Recreate indexes
create index DWO.DW_ARC_CERRORS_MNO on DWO.DW_ARC_CERRORS (MEMBER_NUMBER);
But surpisingly, when I execute the following query, it does not use the index.
SELECT member_number,
COUNT(*) error_count
FROM arc_errors a
WHERE member_number = 68534152 AND
( tx_type = 'SDIC' AND
error_number IN (4, 7, 12, 13, 15, 17, 18, 705) )
OR
( tx_type = 'AUTH' AND
error_number IN (100, 104, 107, 111, 116) )
OR
( tx_type = 'BHO' AND
error_number IN (708,710) )
OR
( tx_type = 'XLGN' AND
( error_number BETWEEN 102 AND 105 OR
error_number BETWEEN 107 AND 120 OR
error_number BETWEEN 300 AND 304 ) )
OR
( tx_type = 'None' AND
( error_number IN (20, 112) OR
error_number BETWEEN 402 AND 421 ) )
OR
( tx_type = 'HYBR' AND
error_number IN (303, 304) )
GROUP BY member_number;
This is what 'explain plan' tell me
SELECT STATEMENT, GOAL = RULE               237907     502923     15087690
SORT GROUP BY               237907     502923     15087690
PARTITION RANGE ALL
TABLE ACCESS FULL     DWO     DW_ARC_CERRORS     237209     502923     15087690
Can someone tell me why a 'table acess full' is required here?
Thanks in advance,
Rajesh

Sorry, I just found the solution myself. I need to put an extra pair of braces around the set of conditions seperated by OR.

SQL Query not using Composite Index

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